1. Field of the Invention
The present invention pertains to the diagnosis of otitis media, and in particular, to systems and methods for classifying tympanic membrane images to aid in properly diagnosing otitis media.
2. Description of the Related Art
Otitis media is a general term for middle-ear inflammation and may be classified clinically as either acute otitis media (AOM) or otitis media with effusion (OME). AOM represents a bacterial superinfection of the middle ear fluid. OME, on the other hand, is a sterile effusion that tends to subside spontaneously. Although middle ear effusion is present in both cases, this clinical classification is important because antibiotics are generally beneficial only for AOM. However, proper diagnosis of AOM, as well as distinction from both OME and no effusion (NOE), require considerable training.
AOM is a frequent condition affecting a majority of the pediatric population for which antibiotics are prescribed. It is the most common childhood infection, representing one of the most frequent reasons for visits to the pediatrician. The number of otitis media episodes is substantial, with approximately 11 million visits to office-based physicians in the US and a total of 16 million prescriptions for antimicrobials related to otitis media yearly. This results in significant social burden and indirect costs due to time lost from school and work, with estimated annual medical expenditures for only direct costs of approximately $2 billion.
The current standard of care in diagnosing AOM includes visual examination of the tympanic membrane with a range of available otoscopes: from simple hand-held ones with a halogen light source and low-power magnifying lens, to more sophisticated videootoscopes and otoendoscopes, which connect to a light source (halogen, xenon or LED) and a computer, and can record images and/or video. Single hand-held otoscopes do not permit acquisition of images and/or video and require diagnosis on the spot. In contrast, videootoscopes and otoendoscopes do permit acquisition of images and/or video. In current practice, the clinician views the feed from a videootoscope or otoendoscope on a side screen while holding the device in the ear canal of an often-squirming young child.
The inherent difficulties in distinguishing among the three diagnostic categories of otitis media (AOM, OME, NOE), together with the above issues, make the diagnosis by non-expert otoscopists notoriously unreliable and lead to a number of problems.
One such problem is over-prescription of antibiotics. More specifically, AOM is frequently over-diagnosed. This happens when NOE or OME is misdiagnosed as AOM, typically resulting in unnecessary antibiotic prescriptions that lead to adverse effects and increased bacterial resistance. Over-diagnosis is more common than under-diagnosis because doctors typically try to avoid the possibility of leaving an ill patient without treatment, often leading to antibiotic prescriptions in uncertain cases.
Another such problem is under-prescription of antibiotics. In particular, misdiagnosis of AOM as either NOE or OME leads to under-diagnosis. Most importantly, children's symptoms are left unaddressed. Occasionally, under-diagnosis can lead to an increase in serious complications, such as perforation of the tympanic membrane, and, very rarely, mastoditis.
Still another problem is increased financial costs and burden, as there are direct and indirect financial costs associated with misdiagnosis, such as medication costs, co-payments, emergency department and primary care provider visits, missed work, and special day care arrangements.
For all the reasons above, accurate diagnosis of otitis media is imperative to ensure that antimicrobial therapy is limited to the appropriate patients. This, in turn, increases the likelihood of achieving optimal outcomes and minimizing antibiotic resistance.